Ag Production and the Environment Text adapted from Leathers & Foster, 2009
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Ag Production and the Environment Text adapted from The World Food Problem Leathers & Foster, 2009 ttp://www.amazon.com/World-Food-ProblemToward-Undernutrition/dp/1588266389 Erosion • Soil removed by – Wind – water • Agricultural cause: – Plowing – bare fields • Absence of roots Wind Erosion http://soils.usda.gov/use/worldsoils/mapindex/eroswind.jpg Water Erosion http://soils.usda.gov/use/worldsoils/landdeg/papers/ersnfig1.jpg Chemical Degradation of Soil • Nutrient depletion – Especially if same crop grown every year • Salinization – Irrigation with low levels of salt • Salt build up when dries • Acidification Salinization http://www.ciseau.org/cds_upload/1118333201256_Thailande.png – – – – – Too much fertilizer Drainage problems Pollutants Oil Pesticides Physical degradation of soil • Less porous – Compaction by • Heavy machines • Animals • Water logging Soil compaction http://www.dpi.vic.gov.au/CA25677D007DC87D/LUbyDesc/Pugged+soil/$File/PUGGED-1.jpg – Roots die – Due to • Over irrigation • Poor drainage Extent of Land Degradation • 38% total cropland degraded worldwide – 2 billion hectares • 83% by erosion • 12% chemical • 5% physical • 5-10 million new hectares – degraded each year • New land must be put into production to compensate Overgrazed degraded soil http://farm3.static.flickr.com/2097/2138777732_5aa323c591.jpg?v=0 – Generally poor quality http://soilerosion.net/image/glasod.gif Irrigation Problems • Water Quality degradation – Salt-water intrusion in coastal areas due to lower water table – Leeches salt into groundwater: unusable – Runoff carries fertilizer, pesticide residues • Land degradation: – – – – Irrigation in Uzbekistan http://www.fao.org/docrep/009/a0409e/A0409E15.jpg SoilErosion Waterlogging Salinization acidification Ag Chemicals • Can lead to – Land degradation – Water pollution – Health problems • Chemical manufacture can be dangerous Union Carbide Chemical Plant, Bhopal India – Explosion at fertilizer plant in Bhopal India in 1984 • Killed thousands Fertilizer Runoff: Hypoxia • Hypoxia – Dead zone in rivers, lakes, oceans – N and P fertilizer runoff cause algae growth – Algal bloom removes dissolved oxygen – Result: nothing grows Carrying Capacity • How many people can earth support? – Carrying capacity • Limitations on – Agricultural land – Fresh water – Waste assimilation http://www.lunaroutpost.com/gallery/earth/images/globe_west_2048.tif.jpg David Pimentel • Believes carrying capacity has already been exceeded • Earth can support 2 billion – at high standard of living • Current yields not sustainable http://ipmworld.umn.edu/vitae/mug/pdmug.gif Julian Simon • Optimistic about future ag production – Technology will solve problems – Drip Irrigation – Fish Farming – GMOs for • Pest resistance • Drought resistance • Salt resistance http://www.indefenceofliberty.org/admin/thumbnail/julian.jpg Fish: the Blue Revolution • World fish stocks fully exploited – No future increases in wild capture • Aquaculture increasing – Developing nations • China – Developing nations by 2020 • 79% World population • 77% World fish consumption http://photos.mongabay.com/07/world_fish_1950-2000-400.jpg Aquaculture http://photos.mongabay.com/07/world_fish_1950-2000-400.jpg https://upload.wikimedia.org/wikipedia/commons/1/10/Global_aquaculture_production_by_ country_2010.png Fish: the Blue Revolution http://www.theglobaleducationproject.org/earth/image.php?image=f-fisheries-map-lg.gif&title=global%20aquaculture Global Warming • Agriculture contributes to global warming: – CO2 released from plant decomposition • CO2 = 80% greenhouse gases • No-till Ag releases less CO2 – Methane released from rice paddies • Methane: 23 x warming impact of CO2 – Nitrous Oxide (NO) released from fertilizer use • NO: 296 x warming impact of CO2 http://picturethis.pnl.gov/PictureT.nsf/All/6GPMKU?opendocument Global Warming • Livestock contribute to GW – Produce 18% of total greenhouse gasses • (Cars, Airplanes, Trains, Boats total 13%) – Cattle Belching produces methane • 200L/d/cow methane – – 1.3 billion cattle in world Occupy 1/3 earth’s landmass • 5% of planet’s greenhouse gasses – Manure produces Nitrous Oxide (NO) – Deforestation to support livestock • Grazing land • Crop land to grow feed • 70% of former forest in Latin America is grazing land http://www.theage.com.au/ffximage/2008/01/22/cow2_wideweb__470x277,0.jpg Global Livestock Distribution Global cattle production is projected to double by 2050 http://cdn.static-economist.com/sites/default/files/20110730_WOC293.gif (2000) http://gristmill.grist.org/images/admin/globalghg.jpg CO2 Emissions http://d35brb9zkkbdsd.cloudfront.net/wp-content/uploads/2015/05/Countries_by_carbon_dioxide_emissions_world_map.jpg http://tomchance.org/wp-content/uploads/2015/03/global-ghg-emissions-figure3-2014.png http://facweb.furman.edu/~mhuntsberger/blogs/com40spring08/b/wp-content/uploads/global_warming_predictions_map_2.jpg http://myearthprints.com/wp-content/uploads/2012/10/NASA+arctic+sea+ice+184+20121.png Global Warming • Impact on Agriculture: – Flooding of coastal land • ½ of world population lives within 120 miles of the coast – Affect crop yields • Increase CO2 – Boosts crop growth – Increase water-use efficiency • Increase extreme weather • Increase insects, disease • Shift climate zones – Northern regions better – Tropical regions worse • Developing countries Impact on Agriculture http://www.imf.org/external/pubs/ft/fandd/2008/03/images/cline5.gif Impact on Agriculture http://earthtrends.wri.org/images/climate_change_agricultural_potential.jpg Ethical Issue • Global warming is caused primarily by CO2 – from industrial development in the first world • Is it morally acceptable that the developing world will suffer more negative effects from global warming – Without having benefited from the fossil fuels that caused the problem. http://jcwinnie.biz/wordpress/imageSnag/468_pollution.jpg Solving Global Warming http://www.zzilch.com/blog/wp-content/uploads/2008/03/combating-global-warming-map.jpg Bioenergy • Potential: – Reduce CO2 emissions • Plants fix CO2 – Sustainable • If use perrennial switchgrass – Profits for farmers • Worldwide – Energy for poor • Worldwide http://www.iowaswitchgrass.com/__images/Switchgrass-Graphic_800.jpg Bioenergy Problems • Competes with food production – Agricultural land diverted – Food prices rise worldwide – Hurts poor hardest • Undernutrition • Ethanol from maize increases CO2 production – Farming uses fossil fuel – Less soybeans planted in U.S. • Tropical forests destroyed to plant soybeans in Brazil. • Net loss of ability to fix CO2 • Biodiesel from oil palm and soybeans destroys rainforests – Oil palm plantations in S.E. Asia – Soybean planting in Brazil Oil Palm Plantation, Indonesia http://image.guim.co.uk/Guardian/environment/gallery/2008/apr/01/biofuels/GD5160468@Thisundated-photo-sh-509.jpg http://media.townhall.com/Townhall/Car/b/20080421RZ1AP-BiofuelGauge.jpg http://cranialcavity.files.wordpress.com/2008/04/ethanolcomic.jpg Bioenergy plusses and minuses http://www.fao.org/clim/docs/CDROM/docs/Bioenergy/Bioenergy_Facts_and_Figures_01.pdf
